In 2012, Adelson and his wife, Miriam, spent at least $93 million backing Newt Gingrich, Mitt Romney and other Republicans in their effort to defeat President Obama and Democrats at every level. These candidates are all too eager to try to court and please the likes of Adelson, who's trying to buy the White House.

But the problem's not just that Adelson is writing blank checks to the candidates of his choosing. The problem is that Adelson and other super-wealthy Republican donors are directing their largesse to buy elected officials who support policies that benefit their bottom lines at the expense of middle-class American families.

People like Sheldon Adelson support candidates who are in favor of lowering tax rates for corporations and the super-wealthy -- people like Sheldon Adelson.

Donna Brazile

But those tax giveaways aren't free. Rep. Paul Ryan's House GOP budget pays for those tax breaks by gutting funding for investments in education and infrastructure, ending Medicare as we know it, and raising taxes on middle-class families with children.

And their focus isn't limited to the White House, or even House and Senate seats. They're opening their checkbook to tip the scales in local races in towns and neighborhoods across the country.

The Washington Post and The New York Times report that the Koch brothers are investing resources in local races, such as county board and small-town mayoral elections. They're exerting their influence in debates over local issues such as property taxes. It's a tall task to stand up to, especially when people like the Kochs are spending with no end in sight.

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Even Gingrich, whose 2012 candidacy was kept alive month after month by Adelson, is now turning on his former patron and his ilk:

"Whether it's the Koch brothers or (George) Soros on the left or Sheldon (Adelson)," Gingrich told the National Journal, "if you're going to have an election process that radically favors billionaires and is discriminating against the middle class — which we now have — then billionaires are going to get a lot of attention."

According to a George Washington University Battleground Poll, about half of Americans know who the Koch brothers are. Considering the lengths that they have gone to keep their involvement in local affairs secret, that figure is a victory for watchdogs and government sunshine groups, not to mention Democrats. But it's alarming for anyone disturbed by their ability to exert disproportionate influence with millions of dollars that represent little more than pocket change to them.

The Koch brothers are legally allowed to flood "dark money" into your town, influencing who represents you in Congress or the Senate, or who sits in your mayor's office. They can do so anonymously, thanks to a ruling by the Supreme Court in Citizens United.

And with the court's recent ruling lifting the cap on the number of candidates Adelson, the Kochs and others can give money to, there seems to be little left in their way.

Even though it's only April, the Koch brothers are already breaking spending records. Americans for Prosperity, one of the Kochs' front groups, has spent more than $30 million since last August running ads in at least eight states. According to The New York Times, AFP has more than "200 full-time paid staffers in field offices in at least 32 states."

It's no coincidence that these targets tend to follow Koch Industries' business interests.

In Michigan, Rep. Gary Peters has called attention to the toxic mountain of petroleum coke -- a byproduct of refining oil sands -- that stands in Detroit and is owned by Koch Minerals. Also called petcoke, the substance poses environmental and public health concerns when the dust blows into the air and water.

In return for his efforts to represent the well-being and safety of his constituents, Peters's bid for the United States Senate has been targeted with millions of dollars in attack ads from the Kochs and AFP. And like the petcoke, the commercials play dirty.

One such ad featured Julie Boonstra, who has cancer, claiming that she lost her doctor under the Affordable Care Act and that insurance became "unaffordable." A fact check showed that neither claim was true and noted that she even experienced "substantial savings" under the law.

No community is too small. AFP's Wisconsin chapter flooded Iron County, home to fewer than 5,000 voting-age residents, with a thousand brochures attacking seven county board candidates as "anti-mine radicals." Another full-color mailing supported the organization's preferred pro-mine candidates.

The dispute? A debate over new mining regulations friendly to Gogebic Taconite and their proposal to construct a $1.5 billion iron ore mine in Iron and Ashland counties. David Fladeboe, state director of Americans for Prosperity, recently admitted, "the mining issue has been a big one for us."

One candidate attacked by AFP told the Milwaukee Journal-Sentinel, "I have a hard time understanding why the Koch brothers think I am such a threat to their well-being — that they single me out in poor little Iron County?" Sure enough, on Election Day, four out of the seven Koch- and AFP-backed candidates won.

Whether billionaires are buying federal candidates who will lower their taxes or local officials favorable to their business interests, their outsized influence is a threat to our democracy, particularly when it is obscured in the form of "dark money."

Middle-class Americans -- who can't afford to buy a school board seat, let alone a U.S. Senate seat -- deserve elected officials and a system that will ensure their voices are heard.